Wind turbine generator

Abstract

To provide a wind power generation device capable of obtaining high power generation efficiency by solving various problems around a windmill wake and smoothly operating an adjacent windmill generator.SOLUTION: A wind power generation device includes a first wind turbine, and a second wind turbine that is provided on a leeward side of the first wind turbine and rotates around the same virtual rotation axis as the first wind turbine by receiving a wake from the first wind turbine, in which a blade of the second wind turbine is configured to rotate in a direction opposite to the first wind turbine by receiving the wake from the first wind turbine.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to horizontal axis wind turbine power generation consisting of a plurality of horizontal axis wind turbine generators, and to a wind power generation device that utilizes wind power, which is a major source of renewable energy. [Background technology]

[0002] The operation of a wind turbine for wind power generation is such that blades fixed to a horizontal or vertical shaft are rotated by wind power, and the rotational force is transmitted to a generator attached to the turbine, thereby generating electrical energy. The wind power generator related to the present invention is a technology that combines multiple horizontal axis wind turbine generators, and the term "wind turbine" in the application documents and specification is an abbreviation for horizontal axis wind turbine generator.

[0003] Wind turbine generators are restricted in where they can be installed due to various conditions, such as environmental regulations and power transmission facilities, and so they are often installed in multiple locations in approved locations.In such cases, they are initially installed in parallel, parallel to the plane of the blades of the primary wind turbine that receives the wind.Depending on the terrain, coastline, or wind direction, it is unavoidable to install secondary wind turbines behind the primary turbine or to the left, right, up, or down, and they are affected by the wake of the primary turbine.

[0004] The airflow that rotates the blades of the primary wind turbine and travels behind the blades becomes turbulent, affecting the rotation of the wind turbines behind and nearby, causing problems in wind power generation operation such as reducing the rotational efficiency of the wind turbine by 10 to 20% or less, or damaging equipment and affecting power generation.This turbulent phenomenon is called wind turbine wake. A wind turbine is designed to receive the wind force of normal atmospheric flow with its blades, generating drag and lift, which in turn converts into rotational energy, and if it receives wind that is turbulent, which is different from this atmospheric flow, it will not operate smoothly. In this specification, turbulent air flow is also referred to as turbulence.

[0005] This turbulence occurs in both wind turbines installed on land and offshore, and the turbulence caused by the wake from the primary turbine diffuses, widening in both the vertical and horizontal directions behind it. In the case of large turbines, this can extend over a wide area of ​​several hundred meters behind and around the turbine. This turbine wake phenomenon has been visualized and confirmed by fog and smoke stream tests. The turbulence phenomenon that hinders the operation of wind turbine generators is an issue related to the operation of wind power generation, which, along with solar power generation, is a major source of renewable energy, and resolving this issue will be a technological breakthrough for renewable energy.

[0006] In the 1990s, a technology called winglets was developed to eliminate turbulence that occurs on aircraft wings. This technology bends the tip of the main wing upwards to eliminate turbulence, thereby increasing lift, reducing fuel consumption by around 5%, reducing noise by around 10%, and reducing the burden of noise control costs during takeoff and landing. It has been found to be economical, and by adopting this technology, domestic aviation companies have seen cost rationalization that exceeds the cost of modification, and have already modified dozens of aircraft. This shows that even a century after the invention of the airplane, there are still many unknowns regarding the nature of interactions between the atmosphere, air currents, and man-made objects. Eliminating the obstacles to wind turbine wakes will increase the amount of power generation output that would otherwise be lost, contributing to the new development of wind power generation, which, along with solar power generation, is a major source of renewable energy. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2024-090396 [Non-Patent Document 1] Announced on October 6, 2023. NEDO New Energy Agency public offering project: "Research and development on observation and evaluation methods for wind turbine wakes." [Non-patent document 2] Press release dated November 8, 2023. Toshiba Energy Systems & Solutions Corporation Summary of the Invention [Problem to be solved by the invention]

[0008] When multiple horizontal axis wind turbine generators are installed and operated, the wind force generated between the turbines becomes turbulent, disrupting or attenuating the wind force received by the surrounding turbines. This turbulence reduces the efficiency of wind power generation at the turbines affected and can sometimes damage the turbines and their equipment. This turbulent phenomenon, wind turbine wake, is a challenge in promoting wind power generation, and is a common issue when installing and operating multiple wind turbines, regardless of their shape or size, whether on land or offshore. When large wind turbine generators are damaged and repaired, they are shut down for a long period of time, resulting in loss of power generation and economic losses in repair costs and manpower. The issue that needs to be resolved is to resolve the above-mentioned issues surrounding wind turbine wakes and ensure the smooth operation of adjacent wind turbine generators.

[0009] The present invention has been made in consideration of the above-mentioned problems of the conventional technology, and has an object to provide a wind power generation system that can solve the various problems related to wind turbine wake and smoothly operate adjacent wind turbine generators to obtain high power generation efficiency. [Means for solving the problem]

[0010] The present invention provides a wind power generation system comprising a first wind turbine and a second wind turbine located downwind of the first wind turbine and rotating around the same imaginary rotation axis as the first wind turbine upon receiving the wake from the first wind turbine, wherein the blades of the second wind turbine are configured to rotate in the opposite direction to the first wind turbine upon receiving the wake from the first wind turbine.

[0011] Preferably, the wind-receiving surface of the first blade of the first wind turbine is inclined at a first angle with respect to an imaginary plane perpendicular to the wind-receiving direction, and the wind-receiving surface of the second blade of the second wind turbine is inclined at a second angle with respect to an imaginary plane perpendicular to the wind-receiving direction in a direction opposite to the inclination of the first blade.

[0012] Preferably, the first angle and the second angle are between 10° and 80°.

[0013] Preferably, the diameter of the outer periphery of rotation of the tip of the first blade of the first wind turbine is approximately the same as the diameter of the outer periphery of rotation of the tip of the second blade of the second wind turbine.

[0014] Preferably, when the diameter of the first wind turbine and the second wind turbine is D and 1 / 10 of D is d, the distance between the first wind turbine and the second wind turbine on the same virtual rotation axis is 6d to 11d.

[0015] Preferably, the first blade and the second blade are in an axisymmetric relationship.

[0016] Preferably, the first blade rotates around a first rotation axis, and the second blade rotates around a second rotation axis that is provided independently of the first rotation axis.

[0017] Preferably, the power generating system has a first generator that generates electricity based on the rotation of the first rotating shaft, and a second generator that is provided independently of the first generator and generates electricity based on the rotation of the second rotating shaft.

[0018] Preferably, it is installed and operated on land or offshore. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide a wind power generation system that can solve various problems related to wind turbine wakes and smoothly operate adjacent wind turbine generators to obtain high power generation efficiency. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram illustrating the shape and positional relationship of a first wind turbine 11 and a second wind turbine 21 of a wind turbine generator 1 according to an embodiment of the present invention. [Figure 2] FIG. 2 is a side view illustrating the positional relationship (distance) between the first wind turbine 11 and the second wind turbine 21. As shown in FIG. [Figure 3] FIG. 3 is a diagram for explaining the fixture 17 for the first blade 13. As shown in FIG. [Figure 4] FIG. 4 is a diagram for explaining the fixture 27 of the second blade 23. As shown in FIG. [Figure 5] FIG. 5 is a diagram for explaining the angles of the first blade 13 and the second blade 23. As shown in FIG. [Figure 6] FIG. 6 is a diagram for explaining the generator M to which the first wind turbine 11 and the second wind turbine 21 are attached. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, a wind turbine generator according to an embodiment of the present invention will be described. The wind turbine generator according to this embodiment has a structure and format in which blades are fixed to a horizontal axis, and is based on a combination of two horizontal axis wind turbine generators with different components. These two wind turbines are subject to different wind forces and operate differently, so they are power generation devices that are distinguished as primary and secondary. Horizontal axis wind turbines used for wind power generation come in a variety of types, including propeller, multi-blade, sail wing, and Dutch type, but the present invention is a means for solving the problem of wind turbine wake that occurs commonly in multiple horizontal axis wind turbine generators installed regardless of these types, the shape and number of blades or blades, and whether the size is large, medium, or small.

[0022] Two horizontal axis wind turbine generators of the same size but with different configurations are prepared, with the turbine that receives the wind power first being the primary turbine, and the secondary turbine located behind it on the same axis and receiving the turbine wake, which is the wake of the primary turbine. "On the same axis" refers to the positional relationship of the wind turbines in which the extension direction of the center of the rotation axis of the primary wind turbine coincides with the center of the rotation axis of the secondary wind turbine. The secondary wind turbine has a different configuration from the primary wind turbine, with the blades that receive the wind facing in the opposite direction to those of the primary wind turbine, and therefore the direction of rotation is also opposite.

[0023] This secondary wind turbine is exposed to the turbulent wind turbine wake, but despite the turbulence, the blades of the secondary wind turbine generate drag, which becomes energy that rotates the wind turbine, allowing it to be operated as a wind turbine generator with almost the same output as the primary wind turbine. This is a wind turbine configuration and function that has been discovered in which the secondary wind turbine receives wind from the wind turbine wake of the primary wind turbine and rotates in the opposite direction to the rotation of the primary wind turbine, utilizing the wind turbine wake as wind power and generating rotational energy similar to that of the primary wind turbine. Furthermore, this technology not only solves the problem of wind turbine wakes, but also leads to the discovery of a new energy source. The combination of the primary side and secondary side is the horizontal axis wind turbine generator of the present invention.

[0024] The utilization of wind power through the development of these secondary wind turbines will involve increasing the power generation output of existing wind turbine clusters by adding additional wind turbines equivalent to secondary wind turbines, doubling the output of existing standalone wind turbines by adding additional secondary wind turbines, increasing the number of units that can be installed and the power generation output of new standalone wind turbine clusters, and installing two units at the same time in new standalone installations.In either case, the number of installations and power generation output will be increased compared to the scale of installation and construction using conventional methods, promoting the development and spread of renewable energy.

[0025] FIG. 1 is a diagram illustrating the shape and positional relationship of a first wind turbine 11 and a second wind turbine 21 of a wind turbine generator 1 according to an embodiment of the present invention. In the example of FIG. 1, the first wind turbine 11 is the primary wind turbine on the windward side, and the second wind turbine 21 is the secondary wind turbine on the leeward side. As shown in FIG. 1, the second wind turbine 21 is provided downwind of the first wind turbine 11, receives the wake from the first wind turbine 11, and rotates around the same imaginary rotation axis 31 as the first wind turbine 11. The blades 23 of the second wind turbine 21 are configured to receive the wake from the first wind turbine 11 and rotate in the opposite direction to the first wind turbine.

[0026] As shown in FIG. 1, the wind-receiving surface of the first blade 13 of the first wind turbine 11 is inclined at a first angle P1 (wind-receiving angle) with respect to an imaginary plane perpendicular to the wind-receiving direction. The wind-receiving surface of the second blade 23 of the second wind turbine 21 is inclined at a second angle P2 in the opposite direction to the inclination of the first blade 13 with respect to an imaginary plane perpendicular to the wind-receiving direction. In this embodiment, the first angle P1 and the second angle P2 are between 10° and 80°.

[0027] FIG. 2 is a side view illustrating the positional relationship (distance) between the first wind turbine 11 and the second wind turbine 21. As shown in FIG. D is the diameter of the wind turbine, d is the spacing distance in units of 1 / 10 of D, and Wt indicates the wind direction.

[0028] 2, the first blade 11 and the second blade 21 have the same diameter. This diameter is the diameter D of the circumference around which the tips of the first blade 13 and the second blade 23 rotate (the outer periphery of rotation of the tips). The first wind turbine 11 and the second wind turbine 21 have the same diameter.

[0029] When the diameter is D, the distance X on the virtual rotation axis between the first wind turbine 11 and the second wind turbine 21 is 0.6D to 1.1D. As shown in FIG. 2, the first blade 13 and the second blade 23 are in a line-symmetric relationship. Furthermore, the first rotating shaft 19 of the first wind turbine 11 and the second rotating shaft 29 of the second wind turbine 21 are provided independently.

[0030] The wind turbine generator 1 is a horizontal axis wind turbine generator that is installed and operated on land or offshore.

[0031] Various embodiments of the present invention will be described below. First Embodiment In large horizontal axis wind turbine generators, for example with a generating capacity of 1,500 kW, the speed-increasing mechanism and generator are large in scale and the installation poles are tall, but even in such large wind turbines, if the primary wind turbine generator (first wind turbine 11) and the secondary wind turbine generator (second wind turbine 21), whose wind-receiving surface faces in the opposite direction and rotates, are installed coaxially at a fixed interval, it becomes a horizontal axis wind turbine generator and can generate high output power under the same installation conditions. If there is economic merit in increasing power output, it would be better to reduce the height of the tower rather than using tall pillars to capture strong winds, which would allow for rationalization of construction, maintenance, and power transmission, thereby contributing to reducing power generation costs.

[0032] Second Embodiment Regardless of the scale, by installing a new wind turbine generator (second wind turbine 21) of the same scale and with a secondary configuration at a certain distance behind an existing wind turbine generator, the amount of power generated can be increased and new renewable energy can be obtained. This is an easy addition rather than a new installation.

[0033] <Third embodiment> Even in areas with little wind or weak winds where wind power generation is difficult to make profitable with the power output of a single unit, if the wind power generation device of this embodiment, which uses multiple wind turbines (two or four units), can be used to increase the power generation output and make it profitable, there will be more opportunities for wind power generation in areas that have previously been considered unsuitable for wind power generation.

[0034] <Fourth embodiment> By making the power generation device having the configuration of the primary and secondary generators (first wind turbine 11 and second wind turbine 21) of this embodiment a general-purpose product that is easy to handle and install, it can be used in unused spaces such as offices, schools, various facilities, homes, and rooftops of buildings in urban areas, as well as on mobile objects such as ships, which will promote the use of renewable energy and raise public awareness, and will also be effective as an emergency power source.

[0035] Examples of the wind turbine generator 1 of this embodiment will be described below together with comparative examples. Up until now, we have been conducting research and development related to elucidating wind turbine wakes as well as airflow and wind conditions using small wind turbine generators, but we have now created a new wind turbine for actual testing. The structure of a typical wind turbine generator consists of a rotor with blades attached, a transmission, a nacelle that houses the generator, and a support that is installed on the ground. The purpose of this test was to observe the wind conditions, wind speed, and the operation and operation of the wind turbine, so the behavior of the wind turbine was measured and observed in detail without a generator attached to the wind turbine, but in the example, tests were conducted with a generator attached. The axis is the rotating shaft of the wind turbine.

[0036] The test equipment used for the actual machine testing was constructed with a cast iron V-pulley with a diameter of 25.6 cm as the rotating plate, an axis fixed to this, two sets of wooden stands supporting the axis on both sides, bearings installed on both stands as support shafts, and the wind turbine positioned in the middle of the stands. The blade is made of a rectangular wooden board, 9cm wide x 55cm long, 1.2cm thick, and has an area of ​​495cm. 2 Four of these were installed to create the Dutch type. The first blade 13 of the first wind turbine 11 and the second blade 23 of the second wind turbine 21 were attached to the rotating plate with their wind-receiving surfaces 13a, 23a facing in different directions.

[0037] As shown in FIG. 1, in the first wind turbine 11, the four first blades 13 that face the wind direction Wt and receive the wind are each fixed to the first rotating device 180 via the first mounting fixture 17 shown in FIG. 3 so that the first angle P1 (oblique angle) of the wind receiving surface 13a faces leftward. FIG. 3 is an external view of the first mounting fixture 17 that fixes the first blade 13 to the first rotating fixture 180 shown in FIG. As shown in FIG. 3, the first mounting fixture 17 has plate-shaped mounting portions 171 and 173 that are integrally molded. The mounting surface of the mounting portion 171 and the mounting surface of the mounting portion 173 form a first angle P1. The attachment portion 171 is fixed (with screws or the like) to a front surface 181 (imaginary surface) of the first rotating tool 180 of the first wind turbine 11 shown in FIG. First blade 13 is fixed to mounting portion 173. As a result, front surface 181 and first blade 13 form a first angle P1.

[0038] As shown in FIG. 1, in the second wind turbine 21, the four second blades 23 that face the wind direction Wt and receive the wind are each fixed to the second rotating device 280 via the second mounting device 27 shown in FIG. 4 so that the first angle P1 (oblique angle) of the wind receiving surface 23a faces leftward. FIG. 4 is an external view of the second mounting fixture 27 that fixes the second blade 23 to the second rotating fixture 280 shown in FIG. As shown in FIG. 4, the second mounting fixture 27 has plate-shaped mounting portions 271 and 273 integrally molded. The mounting surface of the mounting portion 271 and the mounting surface of the mounting 213 form a second angle P2. The attachment portion 271 is fixed (with screws or the like) to a front surface 281 (imaginary surface) of the second rotating tool 280 of the second wind turbine 21 shown in FIG. The second blade 23 is fixed to the mounting portion 273. As a result, the front surface 281 and the second blade 23 form a first angle P1. As shown in FIG. 1, in the second wind turbine 21, the four second blades 23 that face the wind direction Wt and receive the wind are fixed to the disk 15 via mounting fixtures 27 shown in FIG. 4 so that the second angle P2 (oblique angle) of the wind-receiving surface 23a faces rightward. The first angle P1 and the second angle P2 are, for example, 20°. As shown in the plan view of Figure 5, the oblique angle is 0° in the direction perpendicular to the wind direction and 90° in the wind direction.If the first angle P1 of the first blade 13 and the second angle P2 of the second blade 23 are 10° or less, the wind turbine will not rotate smoothly.If they are 80° or more, the wind turbine will rotate, but the drag generated on the blades will be low.Therefore, in order to obtain appropriate rotational energy, the oblique angle range is set to be between 10° and 80°, and in the testing machine of the example, it was set to 20°.

[0039] The actual test was carried out outdoors. The weather conditions were clear, the temperature was 17°C, and the wind speed was 1-2 m / s. Other test days were also conducted under similar climatic conditions except for temperature. To obtain a constant wind speed, a blower output of 150 W was used and the wind speed measurement point was set 50 cm from the center of the front of the wind turbine.

[0040] The first wind turbine 11 was operated alone. The wind speed from the blower was 3.5 m / s and the rotation speed of the windmill was 66 rpm.

[0041] Two first wind turbines 11 of the same structure are arranged in series. The axes were aligned on a virtual coaxial extension, and the spacing was determined starting from the center of both wind turbines. The spacing distance between the two turbines was defined as D, which was the diameter of the first wind turbine 11, approximately 136 cm, and 1d, which was one-tenth of D. The operation of the rear first wind turbine 11 was observed at each spacing distance from 1d to 10d and 12d. It has been found through testing that the spacing between the wind turbines is a distance related to the diameter of the first wind turbine 11 in the front stage, and this knowledge is also applied to the rotation speed of the first wind turbine 11 in the rear stage and the control of the wind turbines. The first wind turbine 11 in the front stage was blown with air at a speed of 3.5 m / s, and the rotation was 66 rpm. Measurement of the rotation of the first wind turbine 11 in the rear stage began at a distance of 1 d from the first wind turbine 11 in the front stage, but rotations from 1 d to 5 d were stopped, rotations 6 d were stopped and the blades vibrated, rotations 7 d and 8 d were also stopped and vibrated, rotations 9 d and 10 d were stopped, and rotations 11 d and 12 d were stopped.

[0042] As a result, the first wind turbine 11 in the front stage rotates at 66 rpm / sec, but the first wind turbine 11 in the rear stage, which has the same blade orientation and rotation direction, does not rotate and remains stopped at all intervals d.This is because it was confirmed that the wake produced when the first wind turbine 11 in the front stage receives the wind and rotates the wind turbine generates a wind turbine wake, which causes operational problems for the first wind turbine 11 in the rear stage that receives the wind.

[0043] A test was conducted to examine the state of rotation of the second wind turbine 21 when the second wind turbine 21, which has a different configuration from the first wind turbine 11, was moved on the coaxial extension of the second wind turbine 21 and the spacing between them was changed. FIG. 2 shows a side view of an arrangement in which the axes of the first wind turbine 11 and the second wind turbine 21 are aligned on an imaginary coaxial extension, with the center of the wind turbine as the starting point. The second wind turbine 21 was placed behind the first wind turbine 11 at a rotation speed of 66 rpm with a wind speed of 3.5 m / sec from the blower, and the state of rotation was observed.

[0044] When the distance X between the first and second wind turbines 11 and 21 was between 1d and 3d, the rotor did not rotate, when X was between 4d and 5d it fluctuated irregularly between 20 and 30 rpm, when X was between 6d and 7d it rotated at 57 rpm, when X was between 8d it rotated at 66 rpm, when X was between 9d it rotated at 72 rpm, when X was between 10d it rotated at 59 rpm, when X was between 11d it rotated at 45 rpm, and when X was between 12d it did not rotate. This progression is shown in Table 1. Table 1 shows the rotational states when X is 1d to 12d at a wind speed of 3.5 m / sec and the rotational speed of the first wind turbine 11 is 66 rpm. Relationship between the distance X between the first wind turbine 11 and the second wind turbine 21 and the rotation speed rpm of the second wind turbine 21

[0045] [Table 1]

[0046] This confirmed the rotation of the second wind turbine 21, which was operating by receiving wind from the wind turbine wake. A test was conducted to examine the basis for the merit of arranging the second wind turbine 21 at the rear of the first wind turbine 11 on a coaxial extension. The second wind turbine 21 was positioned with its rotation axis aligned with an extension of the rotation axis of the first wind turbine 11, with a distance of 9d between them. With a wind speed of 3.5 m / s, the rotation speed of the first wind turbine 11 was 66 rpm, and the rotation speed of the second wind turbine 21 was 72 rpm, when the second wind turbine 21 was moved a distance equivalent to 1d to the left as viewed from the wind-receiving surface, the rotation of the second wind turbine 21 fluctuated, intermittently reaching around 30 rpm, and stopped after a movement of a distance of 2d, and continued to stop when moved further to the left.

[0047] Through this test, it was confirmed that when the second wind turbine 21 is more than 1d away from the virtual coaxial extension of the rotation axis of the first wind turbine 11, the rotation of the blades fluctuates or stops, and that the rotation fluctuates or stops even when the second wind turbine 21 is moved the same distance to the right, upward, or downward. As a result, the rotation of the second wind turbine 21, whose blades have an orientation and rotation direction opposite to those of the first wind turbine 11, can only be realized by positioning its axis on the extension of the center line of the rotation axis of the primary wind turbine.

[0048] The wind speed of the first wind turbine 11 was 3.5 m / s, the rotation speed was 66 rpm, and the rotation speed of the second wind turbine 21 in the subsequent stage was 72 rpm, and the wind speed was measured at an intermediate value between the first wind turbine 11 and the second wind turbine 21. This is to observe the airflow of the second wind turbine 21, which receives wind from the wind turbine wake and operates using this as wind power, and to obtain information about the wind received by the second wind turbine 21. The central measurement point is 50 cm forward of the center of the wind-receiving surface of the second blade 23 of the second wind turbine 21, and the wind speed is 2.5 m / s at the central point, 2.7 m / s 50 cm above, 2.1 m / s below, 2.7 m / s to the left, and 1.8 m / s to the right.This is an extremely unbalanced wind speed in a limited space, but this turbulent airflow gives the second blade 23 rotational energy in the opposite direction, and the wind turbine wake can be used as new energy.

[0049] The first wind turbine 11 and the second wind turbine 21, which have different configurations, were swapped in their locations and subjected to the same wind speed test, but this was under the condition that the blades and rotation directions were swapped. The second wind turbine 21 was the primary wind turbine, and the first wind turbine 11 was the secondary wind turbine, with a spacing X of 9d. At a wind speed of 3.5 m / s, the second wind turbine 21 rotated at 66 rpm, while the first wind turbine 11 rotated at 72 rpm, with no change in the operation of either turbine, and there was no disruption to the operation of the turbines if the orientation of the blades and the direction of rotation were reversed.

[0050] Next, we conducted tests to examine the influence of the wind turbine wake received by the secondary turbine and the operating conditions when the blades of the secondary turbine were made larger than those of the primary turbine. The second windmill 21 has a width of 9 cm, a length of 70 cm, a thickness of 1.2 cm, and an area of ​​630 cm. 2 When the plates of the first wind turbine 11 were replaced with plates of the second wind turbine 21 and four plates were installed, the second wind turbine 21 was placed at the rear 9d of the first wind turbine 11 on the virtual coaxial extension, and was operated and measured. At this time, when the wind speed was 3.5 m / s and the first wind turbine 11 was rotating at 66 rpm, the second wind turbine 21 was rotating at around 40 to 60 rpm, but the fluctuations were large and the rotation speed was unstable. Various causes were assumed, such as the boundary between the range of the wind turbine wake and the outer airflow, and it was found that simply making the blades of the secondary wind turbine larger would make operation unstable, and that a wind turbine of a different scale from the primary wind turbine would be unsuitable.

[0051] Examples of the present invention will be described below, but the application is not limited to these. As an actual machine test, generators were fastened to the first rotating shaft 19 of the first wind turbine 11 and the second rotating shaft 29 of the second wind turbine 21, and the outputs were measured. The first rotary shaft 19 and the second rotary shaft 29 are provided independently.

[0052] FIG. 6 is a diagram for explaining the generator M to which the first wind turbine 11 and the second wind turbine 21 are attached. A V-pulley V1 was attached to the outer shaft of the rear bearing of the first wind turbine 11 and the second wind turbine 21, and a V-pulley V2 was similarly attached to the shaft of the generator M. The generators M used by both the first wind turbine 11 and the second wind turbine 21 have the same specifications. The V-pulley V1 on the wind turbine side had a diameter of 35.4 cm, and the V-pulley V2 on the generator M side had a diameter of 6.3 cm, resulting in a speed-up ratio of approximately 5.6. The generator M was then operated using the V-belt 81, and the power generation output was measured.

[0053] The rating of generator M is three-phase AC 100V, output 1.5KW, rotation speed 500rpm, and two 600W electric heaters were connected as loads, and the output amperes A were measured. At a wind speed of 3.5 m / s, the first wind turbine 11 had a rotation speed of 62 rpm and a current of 59 V and 4.5 A, and the second wind turbine 21 had a rotation speed of 68 rpm and a current of 66 V and 5.5 A, for a total output of 9 A. Since the increased rotation speed by the pulley is calculated as output rotation speed x output side diameter ÷ transmission side diameter, the rotation speed of the generator side pulley V2 of the first wind turbine 11 is 62 x 35.4 ÷ 6.3 ≒ 348 rpm, and V2 of the second wind turbine 21 is similarly approximately 382 rpm. The reason why the rotation speed of the wind turbine is lower than that of no-load operation is due to the load on the generator M.

[0054] Next, two fans were used to test the power output of the wind turbine at a wind speed of 7 m / s. The first wind turbine 11 was 100V, 15A at 106 rpm, and the second wind turbine 21 was 100V, 15A at 116 rpm, with the total output of the two wind turbines acting as a power generating device being 30A. According to the above calculation example, the rotation speed of V2 of the first wind turbine 11 is approximately 595 rpm, and V2 of the secondary wind turbine is similarly 651 rpm. At wind speeds of 7 m / s, high power output is achieved, creating renewable energy.

[0055] The present invention is not limited to the above-described embodiments. That is, those skilled in the art may make various modifications, combinations, subcombinations, and substitutions of the components of the above-described embodiments within the technical scope of the present invention or its equivalents. [Explanation of symbols]

[0056] 1...Wind power generation equipment 11...First Windmill 13...First feather 17...Mounting fixture 19...First rotation axis 21...Second Windmill 23...Second feather 27...Mounting fixture 29...Second rotation axis 31...Virtual rotation axis 61...First support stand 63...Second support stand

Claims

1. The first windmill, a second wind turbine provided downwind of the first wind turbine, receiving a wake from the first wind turbine and rotating around the same imaginary rotation axis as the first wind turbine; and The blades of the second wind turbine are configured to receive the wake from the first wind turbine and rotate in the opposite direction to the first wind turbine. Wind power generation equipment.

2. a wind-receiving surface of a first blade of the first wind turbine is inclined at a first angle with respect to an imaginary plane perpendicular to the wind-receiving direction, The wind-receiving surface of the second blade of the second wind turbine is inclined by a second angle in a direction opposite to the inclination of the first blade with respect to an imaginary plane perpendicular to the wind-receiving direction. The wind turbine generator according to claim 1 .

3. The first angle and the second angle are between 10° and 80°. The wind turbine generator according to claim 2.

4. The diameter of the outer periphery of rotation of the tip of the first blade of the first wind turbine is approximately the same as the diameter of the outer periphery of rotation of the tip of the second blade of the second wind turbine. The wind turbine generator according to claim 3.

5. When the diameter of the first wind turbine and the second wind turbine is D and 1 / 10 of D is d, The distance between the first wind turbine and the second wind turbine on the same virtual rotation axis is 6d to 11d. The wind turbine generator according to claim 4.

6. The first blade and the second blade are in an axisymmetric relationship. The wind power generating system according to claim 5.

7. The first blade rotates around a first rotation axis, and the second blade rotates around a second rotation axis that is provided independently of the first rotation axis. The wind turbine generator according to claim 6.

8. a first generator that generates electricity based on rotation of the first rotating shaft; a second generator that is provided independently of the first generator and generates electricity based on the rotation of the second rotating shaft; The wind power generating device according to claim 7, comprising:

9. Installed and operated on land or offshore The wind turbine generator according to claim 8.

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